Ground roller mounting for lawn mower



April 12,1955 c. w. MOTT GROUND ROLLER MOUNTING FOR LAWN MOWER OriginalFiled July 29, 1948 5 Sheets-Sheet 1' ji z ezzzizz' 62 21.! a/yazz April12, 1955 c. w. MOTT GROUND ROLLER MOUNTING FOR LAWN MOWER Original FiledJuly 29,- 1948 3 Sheets-Sheet 2 422 1 zf/%zz PMQ- M 3 Shets-Sheet 3fivezzzar C. W. MOTT GROUND ROLLER MOUNTING FOR LAWN MOWER OriginalFiled July .29, 1948 April 12, 1955 6627! /J PM M United States PatentGfiice 2,705,861 Patented Apr. 12, 1955 GROUND ROLLER MOUNTING FOR LAWNMOWER Carl W. Mott, Lake Ozark, Mo., assignor to International HarvesterCompany, a corporation of New Jersey 4 Claims. (Cl. 56249) Thisinvention relates to power-driven lawn mowers and wherein there arefeatures particularly useful in such mowers of the walk-behind type.This application is a division of my copending application, Serial No.41,343, filed My 29, 1948, for Power-Driven Lawn Mower.

The embodiment herein disclosed for illustrating the invention comprisesa frame mounted upon a running gear having motor-driven traction wheelsspaced apart transversely of a rear portion of the frame. A powerdrivengrass-cutting rotor assembly extends across a front portion of the frameand has a plurality of knife-like flails pivotally mounted upon arotatable carrier. When the rotor assembly is power driven the flailsswing into the grass for cutting same and chopping it into short pieces.Handles for engagement by an operator walking behind the mower unitproject upwardly and rearwardly from the rear portion of the frame. Aninternal combustion engine is carried by the frame as a power source fordriving the traction wheels and the grass-cutting rotor assembly.

One object of the invention is the provision of a novel ground-engagingroller together with mounting means therefor upon the frame tofacilitate adjustment of the distance between the grass-cutting rotorassembly and the ground surface whereby the length of the stubble ofgrass cut by the mower can be selectively regulated.

Another object is the provision of a grass-cutting mower with laterallyspaced forward side frame portions having a traction wheel support, agrass-stem-engaging bar mounted upon and extended between said forwardframe portions in contiguity with the ground, and a grass-cutting rotorstructure supported by and between the laterally spaced frame portions,such rotor structure including grasscutting flails of which tips extendradially from the rotational axis of the rotor structure during rotationthereof and traverse a linear nadir Zone contiguously above and inparallelism with said bar to cooperate therewith in cutting grass stemsduring rotor rotation.

Still another object is the provision of a grass-cutting mower accordingto the next preceding object and wherein said bar rests slidably uponthe ground to complement the traction wheels for dirigibly supportingthe mower.

The above and other desirable more specific objects inherent in andencompassed by the invention will become apparent from the ensuingdescription, the appended claims, and the drawings, wherein:

Fig. 1 is a side elevational broken view of a motordriven walk-behindlawn mower embodying a preferred form of the invention.

Fig. 2 is a plan view of the mower shown in Fig. l, but omitting thecontrol handles and the internal combustion engine.

Fig. 3 is a rear elevational view of the mower frame, running gear, gearbox, and forward and reverse drive belts through which power istransmittable from gearing in the gear box to the running gear.

Fig. 4 is a front elevational view of the mower, illustrating thegrass-cutting rotor assembly.

With continued reference to the drawings and particularly to Figs. 1, 2and 3, a frame 21 of the mower can be seen to comprise a pair oflaterally spaced plate-like side frame members 22 and 23. These sideframe members are connected together at rear edge portions by across-frame member 24. The cross-frame member 24 may be welded to thetwo side frame members as indicated at 25, in Fig. 2. A semi-cylindricalrotor shroud 26 extends between forward portions of the side framemembers and constitutes means for rigidly connecting these members. Theshroud 26 may be welded to the side frame members as shown at 27, inFig. 2. A semi-cylindrical deflector extension 28 (see Fig. l) of theshroud 26 also extends between the side frame members to which it iswelded at its ends as shown at 27a to constitute a part of the frame andto rigidify same. A grass-stemengaging runner bar 29, Figs. 1 and 4, hasupturned end portions 39 respectively secured to the side frame membersby bolts 31. This runner bar is directly beneath the grass-cutting rotorassembly 32 and limits the proximity with which said assembly canapproach the ground. This runner bar is adapted to slide upon the groundand to cooperate with traction wheels 33 for supporting the frame.

The rotor assembly 32 comprises a shaft 34 extending between and throughthe side frame members 22 and 23 wherein opposite end portions of suchshaft are respectively journaled. There are four sets of axially alignedand axially spaced flail pivot rod holders 35 carried by the shaft 34.These sets of flail pivot rod holders are equally spacedcircumferentially of the shaft. Flail pivot rods 36 are slid endwiserespectivey into these sets of axially aligned holders 35, the upper setof the holders 35 illustrated in Fig. 4 having the rod Withdrawntherefrom. Prior to the endwise insertion of each rod 35 into thetubular holders 35 therefor, pairs of grass-cutting flails 37 will beplaced in beer -to-back relation as illustrated in Fig. 4, and haveapertures 38 in shank portions thereof aligned with and disposed betweenaxially spaced ends of the holders 35 so that as the rod is slid intoplace in the holders it will pass through the apertured shanks of theflails to provide a pivotal support thereto. During rotation of therotor assembly the flails 37 will be caused to swing radially outwardlyfrom the axis of the shaft 34, as ilustrated in Fig. 1, because ofcentrifugal forceI Diverging end portions or tips 39 of each pair ofback-toback arranged fiails 3'7 collide with and cut the grass when therotor assembly is rotated at high speed. The circular path of thesefiail tips cross a linear nadir zone appearing as a point Z in Fig. 1extending in contiguous parallelism with the stem holding runner bar 29to cooperate therewith in clipping grass stems irnmediately above suchbar.

Locomotion of the mower over the ground surface is made easier by aground-engaging roller 41 which is rotatively carried upon a shaft 42having its opposite ends mounted in forward end portions 43a of levers43. These levers 43 are mounted adjacently to the inner sides of theside frame members 22 and 23 where they are pivotally carried upon bolts44. Each side frame member 22 and 23 has an upwardly extending slot 45adjacently to the rear end portion of the associated lever 43. Aplurality of vertically spaced openings 46 is in each of the side framemembers 22 and 23, above the slot 45 therein. A spring mounting memberhaving a head 47 and a shank 43 is associated with each set of openings45. The shank 48 of each headed spring mounting member is inserted inone of the associated openings 45. Subsequent to insertion of the shanks48 through a selected opening 46, a crank nut 49 is turned thereonto, asillustrated in Fig. 2.

A bearing 51 in each spring mounting member head 47 slidably receives avertical rod 52. The lower end portion of each rod is turned laterallyand inserted inwardly through the associated frame member slot 45 intopivotal connection 52a with the rear end of the associated rockablelever 43. An upper end portion of each rod 52 above the spring mountingmember 47 is surrounded by a helical expansion spring 53 which reactsbetween its associated head 47 and a nut 54 on the upper end of itsassociated rod 52 for urging the rod upwardly, thereby urgin the levers43 to pivot in the direction carrying the front ends thereof downwardlyfor pressing the groundengaging roller 4-1 against the ground. In thismanner weight of the mower is transferred from the runner bar 29 ontothe ground-engaging roller, thereby diminishing frictional engagement ofthe runner bar with the ground and diminishing the tractive forcenecessary for causing movement of the mower over the ground surface.

Should it be desired to cause the grass to be cut at greater length thanthe shortest length possible when the runner bar slides along the groundsurface, spring mounting members having heads 47 will be moved upwardlyinto higher of the openings 46 for causing sufficient downwarddisplacement of the ground-engaging roller 41 for transferring all ofthe weight from the runner bar onto such roller and selectively raisingthe runner bar above the ground surface.

A motor M for driving the grass-cutting rotor assembly 32, and also fordriving the traction wheels 33 of the mower, is mounted upon amotor-supporting platform 55, Figs. 2 and 3. The rear end of theplatform 55 is supported upon the transverse frame member 24, whereasthe forward end of such platform is mounted upon the shroud extension28.

The motor M herein illustrated is an internal combustion engine. A gearbox 61 contains gearing (not shown) driven from the engine. Such gearingdrives a shaft 65 extending through a long tubular bearing 66 thereforwhich is integral with a bearing plate 73 mounted in the casing foroscillative movement about a horizontal axis in parallelism with butbelow the shaft 65. Said axis is coaxial with a pivot pin 79, Fig. 1,mounted in the side frame 22 and pivotally supporting the outer end ofthe outboard bearing 66 by virtue of a short arm 77 projectingdownwardly from the bearing into a pivotal mounting upon the pin 79. Ahandle 81 integral with the outboard bearing 66 is manipulatable forrocking the bearing plate 73, bearing 66 and the arm 77 about the pivotaxis coaxial with the pin 79. A pulley 69, Figs. 1 and 2, is mounted onand constrained for rotation with the outer end portion of the shaft 65.Pulley 69 is disposed in a common plane with a pulley 71 mounted on andconstrained for rotation with an outer end portion of the rotor assemblyshaft 34. A belt 72 trained over the pulleys 69 and 71 is adapted totransmit driving force from the pulley 69 to the pulley 71 when thisbelt is tightened by rearward displacement of the outboard bearing 66about the axis of the pin 79. Means unrelated to this invention, butdisclosed in the parent application Serial No. 41,343, is provided forholding the bearing 66 rearwardly displaced following such displacementby use of the handle 81.

Forward motion of the mower is obtained by power derived from the motorM when a forward belt 92 is tightened in driving relation between aforward pulley 93 mounted on the outer end of a driven shaft 94projecting outwardly from the gear box 61. When so tightened the belt 92will transmit power from the pulley 93 to a pulley 95 which is mountedon and constrained for rotation with a cross shaft 96. This cross shaftcarries a sprocket 97 for rotation therewith and from which power istransmitted through a chain 98 to a sprocket 99 incorporated into adifferential casing 101. When the casing 101 is rotated, it causesdifferential rotation of axle shafts 102 and 103 projecting oppositelytherefrom.

'The traction wheels 33 are respectively secured to the axle shafts 102and 103. The axle shafts 102 and 103 which constitute a traction wheelshaft structure 102-403 are carried rotatively in bearing units 104 and105 which are supported in side frame members 23 and 22 of the mowerframe. A running gear for the mower includes the two shafts 102 and 103and the two traction wheels 33.

Power is transmitted from a reverse pulley shaft 106, Fig. 1, to thecross shaft 96 and thence to the running gear of the mower only when theforward belt 92 is loosened and a reverse belt 107 is tightened indriving relation upon a reverse pulley 108, fixed to the shaft 126, anda pulley 109 fixed for rotation with cross shaft 9 The forward pulleyshaft 94 and the reverse pulley shaft 106 are driven in oppositedirections through gearing in the gear box 61. Shaft 106 is constantlydriven while the motor M is operating whereas the forward shaft isdriven at different speeds selectable by adjusting the endwise positionof a shifter rod 126, Fig. 2, projecting horizontally from the gear box.Shifter rod 126 is controlled by a shifter lever 131, Fig. 2, projectingforwardly through a hole 132 in a dependent flange 133 at the rear endof the motor supporting platform 55. The forward end of the lever 131 ispivotally connected at 134 with a member 135 which has a threaded shankportion turned into a threaded recess 136 in the outer end of theshifter rod 126.

Selective tightening and loosening of the forward means of belttightening idlers 139 and 141 rotatively disposed upon a carrier member142, which is rockably mounted upon the cross shaft 96. This oppositelymovable or rockable member 142 normally depends in a neutral positionillustrated in Fig. 1 where neither of the idlers 139 nor 141 pressesagainst its respectively associated belt for tightening the same.Rocking the pivoted member 142 counter-clockwise, as viewed in Fig. 1,will displace the idler 141 more distantly from its associated belt 107while placing the idler 139 in belt tightening relation with respect tothe forward belt 92. Clockwise pivoting of the member 142 from theneutral position shown in Fig. 1 will move the idler 139 farther fromits associated belt 92 pursuant to carrying the idler 141 into belttightening relation with the reverse belt 107.

Rocking of the idler carrier member 142 selectively to and from thepositions on opposite sides of the neutral is accomplished bymanipulating a control element 143, Fig. 1, and a rod element 144 whichis connected to the element 143 by an inverted U-shaped bracket 145slidably on the rod 144, and a helical spring 146 disposed between anend portion 147 of the bracket and a stop 148 on the rod 144. The lowerend of the rod 144 is pivotally connected with the idler carrier 142 bya part 149. Handle members 151 and 152 respectively connected with rearend portions of the side frame members 22 and 23 are interconnected by atransverse tubular brace member 153, Fig. 1. This brace member 153,together with handles 151 and 152, serves as a control support forsupporting the control mechanism for the belt tightening idlers. Abracket 154 mounted on the transverse memher 153 pivotally supports, at155, a pendulous pivot element 156 of toggle mechanism which, inaddition to including said element 156, also includes the rod element144 and an articulated joint structure 157 interconnecting said elements156 and 144. Said joint structure 157 includes a pivot connection 158between the pendulous element 156 and the inverted U-shaped bracket 145.

The toggle mechanism is illustrated in Fig. 1 in a relaxed conditionwhich permits the pendulous belt tightener idler carrier 142 to dependidly in the neutral position. Should the operator desire to cause themower to move forwardly, he will grasp a knob 159 on the control element143 and press forwardly upon this knob. This will cause the pivot 158 ofthe toggle mechanism to swing forwardly to the dotted line positionillustrated in Fig. 1, carrying the pivot 158 above and forwardly of acenter line L passing through the pivot and the pivot 149 at the lowerend of the rod 144. As the toggle mechanism is swung forwardly andupwardly to such dotted line position the rod 144 will be moved endwisedownwardly for pivoting the carrier 142 counter-clockwise and disposingthe belt-tightening idler 139 in tightening relation with the lowerflight of the forward belt 92. During this forward and-upwarddisplacement of the toggle mechanism, the upper leg 147 of the U-shapedbracket 145 will compress the spring 146 and after the pivot 158 crossesthe center line L, the compressed spring 146 will tend to continuecounterclockwise swinging of the element 156 to a limit determined byabutment of the control element 143 with the pivot pin 155. With theforward belt 92 thus tightened and with the toggle mechanism retained inthis over-center position, the motor will be drivingly connected withthe traction Wheels of the mower for causing forward movement thereof.Forward motion of the vehicle will continue until the operator exerts arearward force on the knob 159 for swinging the toggle mechanism intothe Fig. 1 position.

Rearward movement of the mower under power derived from the motor M isobtained by manual movement of the control element knob 159 rearward.This pulls the rod 144 rearwardly and upwardly and thereby rocks theidler carrier 142 clockwise, as viewed in Fig. 1, for placing the idler141 in belt tightening relation with the upper flight of the reversebelt 107. As soon as the rearward manually applied force is relievedfrom the knob 159, the pendulously-supported toggle mechanism will swingforwardly together with the pendulous carrier 142 for reestablishing theneutral condition in which neither of the belts 92 nor 107 is tightened.

Having described a preferred form of the invention with the view ofclearly and concisely illustrating the same, I claim:

1. In a grass-cutting mower, a frame having laterally spaced fore andaft extending side frame members, traction Wheels supporting a rearportion of the frame, a grass-cutting rotor mounted in a forward portionof the frame between said side frame members, a ground-engaging runnerbar having end portions secured respectively to said side frame membersand extending beneath the rotor transversely between the side framemembers to limit approach of the rotor to the ground surface, and meansfor diminishing pressure from the runner bar on the ground surface whilesuch bar remains on the ground surface and without actually lifting theframe comprising a ground-engaging roller disposed transversely of andbetween the side frame members rearwardly of such bar and forwardly ofsaid rear portion of the frame, means mounting said roller upon theframe for vertical movement with respect thereto, and means reactingupon the frame for yieldably urging the roller downwardly intoengagement with the ground surface with a force less than required tolift the frame.

2. In a grass-cutting mower, a frame having laterallyspaced side framemembers extending fore and aft thereof, traction wheels supporting arear portion of the frame, a grass-cutting rotor mounted in andextending between forward end portions of said side frame members, aground-engaging runner bar extending between the side frame memberssubstantially beneath the rotor to slide upon the ground surface andlimit approach of the rotor toward such surface, levers respectivelymounted upon the side frame members for pivoting about a commontransverse axis disposed rearwardly of the rotor and forwardly of saidframe rear portion, a ground-engaging roller extending between saidlevers and journalled therein, said levers being pivotal in onedirection to increase pressure of the ground-engaging roller upon theground surface and thereby shift weight of the mower from the runner baronto said roller, spring mountings respectively upon said side framemembers, springs upon said mountings, means interconnecting the springswith said levers, and said springs being biased to react between saidmountings and said interconnecting means for urging the levers to pivotin the one direction with a force insufiicient to lift the frame anddisplace the runner bar from the ground surface.

3. The combination set forth in claim 2 wherein there is means forchanging the position of the spring mountings upon the side framemembers as an expedient for adjusting the magnitude of the biasing forceof the springs and consequently adjusting the proportion of the weightof the mower carried by the ground-engaging roller.

4. In a mounting for a ground-engaging roller for a grass-cutting mowerhaving laterally-spaced fore and aft extending side frame members andwherein said side frame members are in the form of upright plates havingupwardly extending slots adjacently to lower edge portions thereof andvertically-spaced openings thereabove; substantially horizontal leversdisposed respectively adjacently to inner sides of the side framemembers and pivotally mounted thereon for pivoting about a transverseaxis at intermediate sections of the levers, a groundengaging rollerextending transversely of and journalled upon portions of the leversextending forwardly from their pivotal mountings, said levers havingrear end portions disposed rearwardly from their pivotal mountings,spring mounting members having bearing-containing heads disposedexteriorally of said side frame members and shanks extending from saidheads into selective of the verticallyspaced openings, upright rodsrespectively exteriorally of the side frame members, each rod having alower end portion turned laterally therefrom and extending inwardlythrough the slot in its associated side frame member into pivotalconnection with the rear-end portion of the associated roller supportinglever, each rod extending through the bearing in the associated springmounting member and being reciprocable in such bearing, and helicalexpansion springs disposed about upper-end portions of rods, above saidbearing containing heads and reacting between such heads and upper-endportions of the rods for urging the rods endwise upwardly in thebearings and consequently pressing the ground-engaging roller downwardlyagainst the ground surface References Cited in the file of this patentUNITED STATES PATENTS 818,301 Sayre Apr. 17, 1906 2,013,597 BlydenburghSept. 3, 1935 2,032,784 Worthington Mar. 3, 1936 2,506,054 Agee et alMay 2, 1950 2,589,845 Mott Mar. 18, 1952 2,620,613 Bradley Dec. 9. 1952

